Multifrequency generator



Dec. 11 1923. 1,477,271

F. LowENsTEm MULTIFREQUENCY GENERATOR Original Filed Dec. 9, 1918Patented Dec. 11, 1923.

UNITED STATES 1,477,271 PATENT OFFICE.

FRITZ LOWENSTEIN, OF BROOKLYN, NEW YORK; JOHN C. WAIT ADMINISTRATOR OFSAID FRITZ LOWENSTEIN, DECEASED, ASSIGNOR TO WILLIAM DUBILIER, OF NEWYORK, n. Y.

MULTIFREQUENCY GENERATOR.

Application filed December 9, 1918, Serial No. 265,930. RenewedSeptember 13, 1923.

T 0 on whom it may concern:

Be it known that I, Fnrrz LOWENSTEIN, a citizen of the United States,residin at Brooklyn, in the county of Kings and tate of New York, haveinvented certain new and useful Improvements in MultifrequencyGenerators; and I do hereby declare the following to be a full, clear,and exact clescription of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to dynamo electric machines and particularly to amulti-frequency generator especially suitable for use in connection withwireless telegraph apparatus.

One object of my invention is to produce a simple and compact generatorfrom which currents at any one of several different frequencies may beobtained selectively at any given The field Winding that produces themagnetizing flux in generators may, at times, be damaged by burn-out orotherwise; and it is therefore another object of this invention toprovide a generator construction in which the field. Winding issupported in or on the enclosing generator frame or housing in suchanner that it shall be readily removable replaceable independently ofthe other main elements of the machine and without distur ing suchelements, whereby repair or :repls ent of the winding 1s greatly racnStill another object of the invention is to provide a construction inwhich the rotors and their snp norting means are of such form andarrangement as to be easily insertable into and removable from thegenerator housing without disturbing the other parts of the generation1- especially desirable construction in Whi i the objects of myinvention are at t ained, I provide a structure embodying a plurality ofspaced stators, respectivel" coaxial with rotors carried by a shaftmount ed within the frame or housing of the dynamo electric machine, theremovable end. wall of which has boss that projects axially into theframe and partiy houses the field winding which is mounted in coaxialreis.- tion to the sets of rotors and stators, and most advantageouslyadjacent said end Wall, This manner of mounting the field windingpermits the removal of the winding axially from the housing withoutdisturbing the sets of rotors and stators. The sets of rotors and theirsupport, considered as a whole, form What may be described as a.generally conical structure fitting within the comple- 50 mentarilydisposed sets of stator. The rotor structure is therefore axiallymovable into and out of the housing with a maximum of ease and.convenience. The construction thus generally described and more fully 65hereinafter explained is a particularly advantageous one; but to attainthe same objects, other constructions may be provided that,nevertheless, embody the principles of my invention. It is to beunderstood that 76 the principles of theiuvention can be embodied inboth motors and generators.

The objects and novel features of my in vention will be apparent fromthe following description taken in connection with the Y5 drawing,illustrating typical construction Within the invention,

Fig. is a longitudinal central sections view of muiti-frec iuencygenerator bodying my invention, and

Fig. 2 is a transverse sectional view the same, taken on the line of Figshowing parts broken out to more clea- Y disclose the construction. thestators, rotors, and magnetizing field winding.

Referring to the drawings, the generator frame or housing F comprises aheli substantially cylindricsi body provio with feet ligand end shieldsor walls and 13, secured to the ends of the body i. by bolts 101. TheseWalls close the ends ox. the body and are readily removable therefrom.The generator is provided with driving shaft 14 mounted in ball bearings15, 15, carried in central openings in to end shields 12 and L5, Thebearings 15, are held in position by suitable bearing tainers l6 and 17,secured the end shiev .3; by the bolts 15;, the bearing retainer 17secured to end shield 18 having a cent? opening therein through whichone t? the shaftl projects, and is arranged be coupled to a device, suchas an electric tor, for driving" the gBDQ'iEtlZOR The inn races of theball bearings l5, 15 are retains in position, abutting shouldersprovided on shaft 14;, by nuts 19, locked to the shaft 1 5 by s t-rings20.

The shaft 14- carries a rotor-supporti:

sleeve or holiow cylinder 21 keyed the; 3ml

at 3:2 and limited against endvvise movethereon by the rings 23 disposedWithin the hearing retainers 17 and abutting against the inner'edgesoithe inside races or the ball bearings 15. The end shield 13 has anintegral inwardly projecting boss 24!. provided With a bore 25 that isof sufficient diameter to receive the sleeve 21 the air oetvveen thesleeve and shield being as small as possible. The outer surface of thehoes 2t tapers inwardly to partly encase the annular field Winding 25which produces the magnetizing flux for all the rotor-stator sets. Thewinding 25 is held in place against endvvise movement in said housing bythe end plate or shield 13 and the retaining ring 26 that is secured tothe body 3.0 loy bolts 27.

The rotor-supporting sleeve 21 is adapted to support a number oi rotorstructures, depending on. the number of frequencies desired. in thepresent instance, the generator is designed to generate at any one offour different frequencies and accordingly l have shown fourrotorstructures, 28, 29, 30, and 31, supported thereon, the rotorstructures being built up of laminations and constituting the rotatinelements of the rotor-stator sets A, ld,;& and D. The end rotor 28 abutsagainst the shoulder 32 on the sleeve 21 and the other end rotor 31 isheld in place b a nut that is secured on the screwthreaded reduced end3d of the rotor sleeve. The intermediate rotors 29 and 30 are spacedlrorn' the end rotors 28 and 31 and each other by spacing rings 35.

The number Oil poleson the rotors 28, 29', 30 and 31, ditler from eachother so that when the shalt 1a is rotated at any given speed, currentsof a plurality oi diil'erent frequencies will be generated, in thepresent instance, the number of poles on the ro- 28, 9,9, 30 and 31, are13, 19,20 and 21, spective'ly, the range being small so that t efrequencies produced atone speed, say @1733 r. p E11,, are 5310, 855,900 andf3t5 cycles per second, for example, and, therefore, do iot diher very greatly from one another, but word a nunoher of currents ofdidering frequencies, selectable as desired. The sev eral diderentfrequencies are simultaneously produced and, therefore, current atdifferent frequencies may, if desired, he supplied simultaneously fromthe generator. llt is to he understood the; it is not necessary that thestated speed of rotation and pole number he adhered to, inasmuch asthese rosy he altered to suit various conditions id perrnit thegeneration of currents oi di. erent frequencies, as desired. The, rotorsare progressively cl greater external. d meter "i on-o the rotor 23 therotor t removed from the Winding ml, the teeth or poles the may he keptthe sauce so W utensil cumferential length, so that the same size diesmay be used in cutting the teeth or poles of the various laminationsfrom which the rotors are built. in the present instance, tour stators,36, 37, 38, and 39, are secured to the inner side of the frame 10, thestators being positioned opposite the rotors 28, 29, 30 and 31,respectively, and each stator being provided With the usual windings4:0. This coned or stepped arrangement of the cooperating rotor andstator sets renders it a very simple matter to slide the stators andtheir. support out of the housing Without in any Way disturbing theother parts of the machine, the end place 12 being first removed, ofcourse, to permit this operation.

Suitable terminals (not shown) are pro vided, to which the windings 40of the stators are connected, and from which current may be supplied atthe different frequencies to a load circuit or circuits. Current for theexciting field Winding may be supplied by some suitable source, such asa direct current generator All of the metallic parts of the magneticcircuit, that is, the sleeve Ell, the laminations of the rotocstatorsets A, B, G and D, the frame 10 the end shield 13, should he ofhighpermeahility in order to provide a path oil low reluctance for themagnetic flux.

"the oeration of the generator will he understoo from the foregoingdescription,

I The shaft it being driven at a suitable speed and the eirciting coil25 heing ener ised,

current may be generated at four difi erent frequencies in the generatorillustrated, for any change of speed the h'equencies the four sets ol"rotor-stator elements will change accordingly. A damaged field Wind ingmay readily be removed. by takin the end shield 13, and sliding the Wing out of that end of the housing, Without disturbing the rotor-statorelements and other parts of the machine, and'siniilarly, the rotor setsand their support can he readily moved out of the other end afterremoving shield 12, as already explained, These lcatures areparticularly desirable in machines used lor wireless communication,practically uninterrupted service is essen tial, The generatorillustrated as an ample, is of l Elorvatt capacity, lining signed foruse with Wireless telegraph initting devices and developing 10 ans-pr atvolts, when driven. at 2700 revolutions per minute. However, size andthe ap plication of the generain-r are not limited to those given.

While l have shown and described the dynamo electric machine in detail,it w ll be understood that various lectures tha l may he modifiedwithout departing the spirit and principles or: my invention.

it claim:

lr lo a dynamo electrie machine, the comill lltl

llll

bination with a plurality of stators arranged in sets of differentinternal diameters, of a corresponding number of rotors arranged in setsof different external diameters re spectively cooperating with the setsof stators, said diameters decreasing regularly from one end of themachine toward the other, and means for producing a magnetizing flux insaid stators and rotors.

2. In a dynamo-electric machine, the combination with a frame, of aplurality of sets of stators secured therein, said sets of stators beingof different internal diameters and having poles of substantially thesame size, said diameters decreasing regularly from one end of themachine toward the other, windings on said stators, a rotatable shaftmounted in said frame, a plurality of sets of rotors removably mountedas a structural unit on said shaft and respectively disposedconcentrically to said sets of stators, said sets of rotors being alsoof difl'erent external diameters oorrespondin to the stator setdiameteis and having po es of substantially the same size, a separablehousing plate at the end of the frame adjacent the stator set ofgreatest diameter, and means whereby a magnetizing flux is produced insaid rotors and stators.

3. In a dynamo-electric machine, the oombination with housing meansprovided with removable end. Walls, of a plurality of sets ofcooperating disposed within said frame, said sets decreasing in diameterfrom a location adja cent one of said end walls, and a field windingreniovably disposed adjacent the other end wall.

In testimony whereof I hereunto aifix my signature.

FRITZ LOWENSTEIN.

Witness P. A. NEWMAN.

rotors and stators removably

